Although ruminal acidosis typically involves a lowering of ruminal pH to below pH 5.5 to 5.6, it is generally not adequate to define ruminal acidosis as being caused by low ruminal pH. Ruminal acidosis often occurs under intensive management. The ruminal problems are typically a result of dietary management, such as misfeeding of the ration (e.g., single large or xe2x80x9cslugxe2x80x9d feedings) or feeding of highly digestible carbohydrates, underfeeding of effective fiber, or all of the above. The degree of ruminal acidosis can vary from cases of indigestion with a mild scour to cases of sudden death or a very severe and distressing illness resulting in death (Braun et al., 1992). The outlook may often be poor and it may lead to complications, such as pregnancy toxemia.
Acute acidosis presents specific signs and symptoms which, if caught in time, can be treated directly. Sub-clinical acidosis, however differs in many respects from the acute form. Sub-clinical, or chronic, ruminal acidosis is best described as a syndrome related to a fermentative disorder of the rumen. Clinical symptoms of sub-clinical acidosis frequently may go undetected. Often times, sub-clinical acidosis is found in well-managed, high producing herds. Changes in an animal""s ration (i.e., adequate effective fiber, altering forage: concentrate rations, feeding strategies, etc.) influence ruminal pH which can affect the occurrence of sub-clinical acidosis.
Sub-clinical acidosis is a temporarily altered rumen state which causes some aberration in patterns of fermentation and decreased in pH of the rumen, however, intensity and duration are not adequate to cause immediate overt clinical signs. Often times sub-clinical acidosis is dismissed for other problems, such as poor forage quality, poor bunk management, etc. and is not addressed. The challenge is that other disease processes also can cause symptoms listed previously.
The major clinical manifestation of sub-clinical acidosis is reduced and/or cyclic feed intake. Other associated signs include: decreased efficiency of milk production, reduced fat test, poor body condition despite adequate energy intake, high culling rate, unexplained diarrhea, and episodes of laminitis.
Although there are guidelines, high producing cows consuming large quantities of grain (55 to 60% of dry matter intake) will have a tendency toward lower ruminal pH""s during the day. The critical question yet to be addressed is how low can pH go, and for how long before negative effects will be demonstrated?
There are different physiological occurrences that normally take place in a cow""s transition through the lactation cycle which predispose her to higher risks of acidosis. During the transition period and through 50 days postpartum, management of the cow mediated events play an important role in the development of acidosis. Interpretation in the xe2x80x9cnormal ecological balancexe2x80x9d within the rumen can ultimately play a role in predisposing the animal to sub-acute acidosis. When intake is reduced, energy metabolism of the rumen microorganisms as well as the host system is affected. Intake is controlled by a balance of physical mechanisms and mechanisms of the rumen environment. The challenge is to ensure that both mechanisms are working together in such a manner that one does not overpower the other (i.e., too high grain, and/or fermentable carbohydrate versus too much forage). Although there are several factors (i.e., heat, cold facilities, management, diet composition, etc.) that influence intake, managers ultimately must anticipate and compensate for intake challenges associated with normal daily practices on a given farm.
Therefore, ruminal acidosis can have a tremendous negative economic impact, such that it drains productive efficiency potential from dairy herds. The costs associated with sub-clinical ruminal acidosis are often difficult to accurately identify. Setting a confirmed cause and effect to allocate health disorders to chronic acidosis is the problem. Factors to consider include each case of digestive upset, each cow that is culled for laminitis-related lameness, reduced production because cows eat less because they have sore feet or digestive upset, reduced feed efficiency that depresses the nutrient value of feeds even though the price paid per ton remains, and similar considerations. The potential costs to the dairy industry are huge. The present methods of preventing or detecting acidosis are not optimally effective in resolving and/or managing the problem.
The only determinative diagnostic test of sub-clinical acidosis is ruminal pH. Sampling the rumen pH by stomach tubing is plagued with false interpretation because of saliva contamination. Rumen cannulation is the preferred method of obtaining representative samples of rumen fluid, although this has traditionally been used only for research purposes because of the large size of the fistula or cannula that is created and used. The installation of such a large device in the animal and the resulting impact of that installation and residency greatly reduces the economic sale value of the animal. The market value of the animal, with a large fistula in its side is drastically reduced or lost completely. Rumenocentesis or percutaneous needle aspiration as a means of collecting rumen fluid for diagnosis of sub-clinical acidosis in dairy herds has also been used but is very labor and cow-handling intensive.
What is still needed is better equipment and methods for detecting and/or monitoring ruminal pH.
The present invention includes an apparatus and method to use the same. The apparatus comprises an external aspect at the outside of the animal, an indwelling ruminal aspect; and an intermediate aspect between the external and indwelling aspects. The indwelling aspect further comprises a pH sensor; and the external aspect further comprises a housing and a means for storing data from the pH sensor in said housing.